Aromatic carbodiimides, methods for their production and their use

Description

[0001] Carbodiimides have proven themselves in many applications, e.g. as hydrolysis inhibitors for thermoplastics, polyols, polyurethanes, triglycerides and lubricating oils.

[0002] Highly hindered polycarbodiimides are preferably used for this purpose, but these are produced from very special raw materials and are therefore very expensive to purchase. Highly hindered carbodiimides, such as those based on triisopropylphenyl isocyanate, also have very high melting points, are insoluble and cannot be incorporated into the starting materials of the polyurethanes, or can only be done with considerable expenditure of equipment and time. Aromatic carbodiimides based on cheaper raw materials, as described in EP 2997010 B1, for example, can achieve very good hydrolysis protection in some ester-based polymers such as PET or PLA, but have the disadvantage that they do not provide sufficient protection against hydrolysis in other applications, such as polyurethane, and therefore cannot be used universally.State-of-the-art carbodiimides are often in a form that is difficult to dose, particularly in the form of a sticky mass. CN105778026A discloses carbodiimides, their preparation, and their use as hydrolysis stabilizers in polyurethanes, although they have inherent disadvantages regarding their solubility in polyester and their dosability.

[0003] There is therefore a need for new carbodiimides that do not have the disadvantages of the state of the art, are easy to prepare, have high thermal stability, achieve excellent hydrolysis protection even in polyurethane applications and are also easier to dose.

[0004] Surprisingly, this task could be solved by carbodiimides of the formula (I) in the R can be the same or different and is selected from -NCN-RI< and -NHCOOR III<, where RI< is C1-C22alkyl, C6-C12cycloalkyl, C6-C18aryl or C6-C18aralkyl, preferably triisopropylphenyl and R III< is an alkylated polyoxyalkylene radical, R1<, R2< and R3< each independently of one another are methyl, i-propyl or n-propyl, where on each benzene ring one of the radicals R1<, R2< and R3< is methyl and n is from 0 to 500, preferably n is from 1 to 50.

[0005] The molar mass of the alkylated polyoxyalkylene radical is preferably at least 200 g / mol, particularly preferably from 200 to 600 g / mol and most preferably from 350 to 550 g / mol.

[0006] The carbodiimide content (NCN content, measured by titration with oxalic acid) of the carbodiimides according to the invention is typically 2-17 wt.%. To determine the NCN content, the NCN groups are reacted with excess oxalic acid, and the unreacted oxalic acid is then back-titrated potentiometrically with sodium methylate, taking the blank value of the system into account.

[0007] Preferred are carbodiimides where R 1< , R 2< and R 3< each independently represent methyl or i-propyl.

[0008] Preferred are carbodiimides of the formula (I) wherein R is NCN-R I<, where n is from 0 to 500, preferably from 1 to 100 and most preferably from 1 to 50 and the carbodiimide content is preferably 10-17% by weight, particularly preferably 11-15% by weight and most preferably 13-14% by weight.

[0009] A further preferred embodiment relates to carbodiimides of the formula (I) wherein R is NHCOOR III<, where n is from 0 to 20, preferably from 1 to 10, particularly preferably from 3 to 8 and the carbodiimide content is preferably from 4 to 13 wt.%, particularly preferably from 10 to 13 wt.%.

[0010] Carbodiimides of the formula (I) with R = -NCN-R I< , where R I< has the above meaning and R 1< , R 2< and R 3< each independently represents methyl or i-propyl, where on each benzene ring one of the radicals R 1< , R 2< and R 3< is methyl, are solid and have softening points > 40°C. They are therefore excellently suited for the stabilization of ester-based polymers, preferably polymers selected from polyester polyols, polyethylene terephthalate (PET), polybutylene terephthalate (PBT), polytrimethylene terephthalate (PTT), copolyesters such as modified polyesters of cyclohexanediol and terephthalic acid (PCTA), thermoplastic polyester elastomers (TPE E), ethylene vinyl acetate (EVA), polylactic acid (PLA) and / or PLA derivatives, polybutylene adipate terephthalates (PBAT), polybutylene succinates (PBS), polyhydroxyalkanoates (PHA), polyurethane elastomers, preferably thermoplastic polyurethanes (TPU), and blends, such as preferably PA / PET or PHA / PLA blends.

[0011] The invention also relates to a process for stabilizing the ester-based polymers by adding the aforementioned carbodiimides. The aforementioned carbodiimides are preferably added to the ester-based polymers using solids dosing units.

[0012] Solids dosing units within the meaning of the invention are preferably: single-, twin- and multi-screw extruders, continuously operating co-kneader (Buss type) and discontinuously operating kneader, e.g. of the Banbury type.

[0013] In a further embodiment of the invention, carbodiimides of the formula (I) are preferred, where R is -NHCOOR III< and R III< is alkylated polyoxyalkylene and R 1< , R 2< and R 3< each independently of one another are methyl or i-propyl, n is from 0 to 20, preferably n is from 1 to 10, particularly preferably from 1 to 4 and most preferably from 2 to 3 and the carbodiimide content is preferably from 2 to 10% by weight, particularly preferably from 4 to 8% by weight and most preferably from 5 to 7% by weight.

[0014] Preferred alkylated polyoxyalkylene radicals are monoalkylated polyethylene glycol ethers, particularly preferably polyethylene glycol monomethyl ethers, in particular those with molecular weights of 200 - 600 g / mol, preferably of 350 - 550 g / mol.

[0015] The above-mentioned carbodiimides of formula (I) with R = -NHCOOR III< , where R III< is an alkylated polyoxyalkylene radical, are usually liquid at room temperature and therefore - in contrast to most solid carbodiimides - also allow incorporation into liquid polyester polyols, which are used for the production of TPU and PU foams.

[0016] The invention therefore also relates to a process for stabilizing TPU and PU foams, wherein the aforementioned carbodiimides are added to the liquid polyester polyols from which the TPU and PU foams are produced.

[0017] The invention further relates to a process for stabilizing ester-based oils and / or lubricants or greases, wherein the aforementioned carbodiimides are added to the ester-based polymers.

[0018] The concentration of the carbodiimides of the formula (I) according to the invention in ester-based polymers, or in ester-based oils, lubricants or greases is preferably from 0.1 to 5 wt.%, preferably from 0.5 to 3 wt.%, particularly preferably from 1 to 2 wt.%.

[0019] The carbodiimides according to the invention preferably have average molecular weights (Mw) of 1000 to 20000 g / mol, preferably of 1500 to 5000 g / mol, particularly preferably of 2000 to 4000 g / mol.

[0020] Furthermore, carbodiimides are preferred which have a polydispersity D = Mw / Mn of 1.2 to 2, particularly preferably of 1.4 to 1.8.

[0021] The scope of the invention encompasses all of the above and below listed general or preferred ranges of radical definitions, indices, parameters and explanations among each other, thus also between the respective ranges and preferred ranges in any combination.

[0022] The present invention also relates to the preparation of the carbodiimides according to the invention by carbodiimidization of aromatic diisocyanates of the formula (II) with elimination of carbon dioxide at temperatures of 80 °C to 200 °C in the presence of catalysts and optionally solvents and the subsequent functionalization of the free NCO groups with alcohols of the formula NOR III< , where R 1< to R 3< and RI< to R III< have the meanings given for the compounds of the formula (I).

[0023] In this process, aromatic diisocyanates of the formulas (III) and / or (IV) are preferably used as aromatic diisocyanates of the formula (II):

[0024] Particular preference is given to using mixtures of the diisocyanates of formulas (III) and (IV), preferably in a ratio of 60:40 to 95:5, particularly preferably 70:30 to 90:10.

[0025] The aromatic diamines required for the production of diisocyanates can be prepared—as is known to those skilled in the art—by Friedel-Crafts alkylation of the corresponding toluenediamines with the corresponding alkene or haloalkane. These diamines are then reacted with phosgene to form the corresponding diisocyanate.

[0026] To prepare the carbodiimides according to the invention, the diisocyanates, e.g., of formula (III) and / or (IV), can be condensed at elevated temperatures, preferably temperatures of 80-200°C, more preferably of 100-180°C, most preferably of 120-140°C, advantageously in the presence of catalysts and optionally another monoisocyanate of group R1<, with elimination of carbon dioxide. Suitable processes for this purpose are described, for example, in DE-A 1130594 and DE-A 11564021.

[0027] In one embodiment of the invention, phosphorus compounds are preferred as catalysts for the preparation of the compounds of formula (I). Phosphole oxides, phospholidines, or phospholine oxides, as well as the corresponding phospholene sulfides, are preferably used as phosphorus compounds. Further catalysts that can be used are tertiary amines, basic metal compounds, alkali metal or alkaline earth metal oxides or hydroxides, alkoxides or phenolates, carboxylic acid metal salts, and nonbasic organometallic compounds.

[0028] Carbodiimidization can be carried out either in bulk or in a solvent. Alkylbenzenes, liquid paraffins, polyethylene glycol dimethyl ether, ketones, or lactones are preferred solvents.

[0029] In one embodiment of the present invention, the temperature of the reaction mixture is reduced to 50-120°C, preferably 60-100°C, particularly preferably 80-90°C, and the catalysts are distilled off under reduced pressure. In a preferred preparation variant of the carbodiimides according to the invention, the excess diisocyanate is then distilled off at temperatures of 150-200°C, preferably 160-180°C. The free terminal isocyanate groups of the carbodiimides are then reacted with alcohols, preferably in a slight excess of -OH groups, optionally in the presence of a PU catalyst known to the person skilled in the art, preferably tert-amines or organotin compounds, particularly preferably DBTL (dibutyltin dilaurate) or DOTL (dioctyltin dilaurate).The molar ratio of alcohols to carbodiimides is preferably 1.005-1.05:1, particularly preferably 1.01-1.03:1, based on the N=C=O groups present.

[0030] In a further embodiment of the present invention, in order to interrupt the carbodiimidization, the temperature of the reaction mixture is reduced to a value in the range from 50 to 120 °C, preferably from 60 to 100 °C, particularly preferably from 80 to 90 °C and, if appropriate, after addition of a solvent, preferably selected from the group of alkylbenzenes, particularly preferably toluene, the free terminal isocyanate groups of the carbodiimides are reacted with alcohols, preferably in a slight excess of -OH groups, if appropriate in the presence of a PU catalyst known to the person skilled in the art, preferably tert. Amines or organotin compounds, particularly preferably DBTL (dibutyltin dilaurate) or DOTL (dioctyltin dilaurate). The molar ratio of alcohols to carbodiimides is preferably from 1.005 to 1.05:1, particularly preferably from 1.01 to 1.03:1, based on the N=C=O groups present.

[0031] After the reaction is complete, the catalyst and, if present, the solvent are distilled off, preferably at temperatures of 80-200°C under reduced pressure.

[0032] The present invention also relates to a further process for preparing the carbodiimides according to the invention by partial, preferably < 50%, functionalization of the free NCO groups of aromatic diisocyanates of the formula (II) with alcohols of the formula HOR III< and subsequent carbodiimidization with elimination of carbon dioxide at temperatures of 80 °C to 200 °C in the presence of catalysts and optionally solvents, where R 1< to R 3< and R III< have the meanings given for the compounds of the formula (I).

[0033] In this process, aromatic carbodiimides of the formula (III) are also preferred as aromatic carbodiimides of the formula (II) and / or the formula (IV) used.

[0034] The carbodiimides of the invention are preferably purified after their preparation. The crude products can be purified by distillation and / or extraction with solvents. Suitable solvents for purification include polyethylene glycol dimethyl ether, alkylbenzenes, liquid paraffin, alcohols, ketones, or esters. These are commercially available solvents.

[0035] The present invention also relates to the preparation of the carbodiimides according to the invention by carbodiimidization of aromatic diisocyanates of the formula (II) with elimination of carbon dioxide at temperatures of 80 °C to 200 °C in the presence of catalysts and optionally solvents, wherein monoisocyanates of the formula OCN-R I< are added before, during or after the carbodiimidization of the diisocyanates and wherein R 1< to R 3< and RI< have the meanings given for the compounds of the formula (I). If the diisocyanates are added after carbodiimidization, the carbodiimidization is continued in order to convert remaining isocyanate (end) groups of carbodiimides with monoisocyanate into groups of the formula -NCN-R I<. If the monoisocyanates are added before or during the carbodiimidization of the diisocyanates, the functionalization of the end groups takes place automatically during the carbodiimidization.

[0036] In this process, aromatic diisocyanates of the formula (III) are also preferred as aromatic diisocyanates of the formula (II) and / or the formula (IV) used.

[0037] Triisopropylphenyl isocyanate is preferred as monoisocyanate.

[0038] The present invention further relates to a composition containing at least one ester-based polymer, and at least one carbodiimide of the formula (I) according to the invention.

[0039] The ester-based polymers are preferably polymers selected from polyester polyols, polyethylene terephthalate (PET), polybutylene terephthalate (PBT), polytrimethylene terephthalate (PTT), copolyesters such as modified polyesters of cyclohexanediol and terephthalic acid (PCTA), thermoplastic polyester elastomers (TPE E), ethylene vinyl acetate (EVA), polylactic acid (PLA) and / or PLA derivatives, polybutylene adipate terephthalates (PBAT), polybutylene succinates (PBS), polyhydroxyalkanoates (PHA), polyurethane elastomers, preferably thermoplastic polyurethanes (TPU), and blends, such as preferably PA / PET or PHA / PLA blends.

[0040] In a particularly preferred embodiment of the invention, the ester group-containing polymers are thermoplastic polyurethanes (TPU).

[0041] The concentration of the carbodiimide of the formula (I) according to the invention in the composition according to the invention is preferably 0.1 - 5 wt.%, preferably 0.5 - 3 wt.%, particularly preferably 1 - 2 wt.%.

[0042] The polyester polyols as ester-based polymers are preferably long-chain compounds which preferably have a molecular weight (in g / mol) of up to 2000, preferably between 500 - 2000 and particularly preferably between 500 - 1000.

[0043] The term polyester polyols in the sense of the invention includes both long-chain diols and triols, as well as compounds with more than three hydroxyl groups per molecule.

[0044] It is advantageous if the polyester polyol has an OH number of up to 200, preferably between 20 and 150, and particularly preferably between 50 and 115. Polyester polyols that are reaction products of various polyols with aromatic or aliphatic dicarboxylic acids and / or polymers of lactones are particularly suitable.

[0045] The polyester polyols used in the invention are commercially available compounds which are available from Covestro Deutschland AG under the trade name Baycoll ®< or Desmophen ®<.

[0046] The present invention further provides a process for preparing the carbodiimides of the formula (I) according to the invention where R = -NCN-R I< , in which the melt is pelletized after carbodiimidization, either unpurified or after purification, preferably on pelletizing belts. Common pelletizing systems as well as common granulation systems can be used. These are available, for example, from Sandvik Holding GmbH or GMF Gouda.

[0047] Particularly suitable are the carbodiimides of the formula (I) according to the invention with R = -NCN-R I< , and RI< = triisopropylphenyl.

[0048] The present invention also relates to the use of the carbodiimides according to the invention as protection against hydrolytic degradation in ester-based polymers, preferably polymers selected from polyester polyols, polyethylene terephthalate (PET), polybutylene terephthalate (PBT), polytrimethylene terephthalate (PTT), copolyesters such as modified polyesters of cyclohexanediol and terephthalic acid (PCTA), thermoplastic polyester elastomers (TPE E), ethylene vinyl acetate (EVA), polylactic acid (PLA) and / or PLA derivatives, polybutylene adipate terephthalates (PBAT), polybutylene succinates (PBS), polyhydroxyalkanoates (PHA), polyurethane elastomers, preferably thermoplastic polyurethanes (TPU), and blends, such as preferably PA / PET or PHA / PLA blends, or in triglycerides, preferably trimethylolpropane trioleate (TMP oleate), in oil formulations for the Lubricant industry, in PU adhesives, in PU casting resins. Use in urethanes includes, among others:PU foams, PU coatings for wood, leather, synthetic leather, and textiles. Particularly preferred is their use in thermoplastic polyurethanes (TPU).

[0049] The following examples serve to illustrate the invention without limiting it. Examples of implementation Tested were:

[0050] 1) CDI A: a solid carbodiimide with an NCN content of approximately 12 wt.%, based on approximately 80 wt.% 2,4-diethyltoluoyl diisocyanate and 20 wt.% 2,6-diethyltoluoyl diisocyanate, end-functionalized with cyclohexanol (comparative example analogous to EP 2997010 B1). 2) CDI (B): a highly viscous carbodiimide with an NCN content of approximately 14 wt.%, based on 80 wt.% 2,4-diethyltoluoyl diisocyanate and 20 wt.% 2,6-diethyltoluoyl diisocyanate, end-functionalized with -NCN-RI<, where RI< = triisopropylphenyl and n > 40 (comparative example). 3) CDI (C): a solid polymeric carbodiimide with an NCN content of approximately 14 wt.% based on diisopropyltoluoyl diisocyanate (formulas III and IV in a weight ratio of approximately 1:4), end-functionalized with -NCN-RI<, where RI< = triisopropylphenyl and n > 40 (inventive example). 4) CDI (D): a solid polymeric carbodiimide based on diisopropyltoluoyl diisocyanate, end-functionalized with ethylamine (comparative example analogous to CN 105778026).5) CDI (E): a solid polymeric carbodiimide with an NCN content of approximately 6-7 wt.% based on diisopropyltoluoyl diisocyanate (formula III and IV in a weight ratio of approximately 1:4), end-functionalized with methylpolyethylene glycol (Mw approximately 550 g / mol), where n = 4-5 (inventive example). Ester-based polymers:

[0051] 6) Non-stabilized thermoplastic polyurethane (TPU) available from Covestro AG under the name Desmopan. Production of carbodiimides CDI (A)

[0052] In a 250 ml four-necked flask, which had been annealed and filled with nitrogen, 150 g of diisocyanates and 37.5 g of cyclohexanol were placed under a nitrogen stream. After adding 50 mg of 1-methylphospholene oxide, the mixture was slowly heated to 180 °C. Carbodiimidization was then carried out at 180 °C until an NCO content of < 1 wt.% was reached. Production of the carbodiimide CDI (B) and CDI (C):

[0053] In a 250 ml four-necked flask, which had been baked and filled with nitrogen, 150 g of the diisocyanates and 37.5 g of triisopropylphenyl isocyanate were placed under a nitrogen stream. After adding 50 mg of 1-methylphospholene oxide, the mixture was slowly heated to 180 °C. Carbodiimidization was then carried out at 180 °C until an NCO content of < 1 wt.% was reached. Production of the carbodiimide Permanent contract (D)

[0054] In a 250 ml four-necked flask, which had been annealed and filled with nitrogen, 150 g of the diisocyanates and 7.0 g of ethylamine were placed under a nitrogen stream. After adding 50 mg of 1-methylphospholene oxide, the mixture was slowly heated to 180 °C. Carbodiimidization was then carried out at 180 °C until an NCO content of < 0.1 wt.% was reached. Production of the carbodiimide Permanent contract (E)

[0055] In a 250 ml four-necked flask, which had been annealed and filled with nitrogen, 150 g of the diisocyanates and 100 g of MPEG (methylpolyethylene glycol, Mw of approximately 550 g / mol) were placed under a nitrogen stream. After adding 50 mg of 1-methylphospholene oxide, the mixture was slowly heated to 180 °C. Carbodiimidization was then carried out at 180 °C until an NCO content of < 0.1 wt.% was reached. Hydrolysis protection in thermoplastic polyurethane (TPU)

[0056] To evaluate the hydrolysis protection effect in TPU, 1.5 wt.% of each of the carbodiimides under investigation was dispersed into TPU using a Werner & Pfleiderer ZSK 25 laboratory twin-screw extruder prior to the measurement described below. The standard test specimens used to measure tear strength were then produced from the resulting granules on an Arburg Allrounder 320 S 150-500 injection molding machine.

[0057] For the hydrolysis test, these standard test specimens were stored in water at a temperature of 80°C and their tensile strength was measured in MPa.

[0058] The results are listed in Table 1: Table 1 Tensile strength (MPa) Example 1 (cf.) (TPU) Example 2 (cf.) (TPU, CDI A) Example 3 (cf.) (TPU / CDI D) Example 4 (req.) (TPU / CDI E) 0 days 30 30 31 32 5 days 28 30 30 32 10 days 26 30 30 31 15 days 12 28 30 30 20 days 6 25 30 30 30 days 0 5 28 30 80 days - - 18 30 85 days - - 5 29 90 days - - 28 cf. = comparative example, req. = according to the invention

[0059] The results from Table 1 show that the carbodiimides according to the invention provide significantly better hydrolysis protection in TPU compared to the prior art. Solubility in polyester polyol

[0060] Ester-based TPU elastomers are generally stabilized against hydrolysis directly during production. For this purpose, the carbodiimide is typically added to the polyester polyol or polyester plasticizer before the reaction with isocyanates to form the polyurethane. For this reason, the solubility of the carbodiimide plays an important role. Table 2 shows the various carbodiimides in a standard polyester polyol based on adipic acid and ethanediol with an Mw = 2000 (Desmophen 2000 MM from Coverstro AG) at 80 °C. Table 2 Solubility in polyesterpolyol Example 5 (cf.) (CDl D) Example 6 (req.) (CDI E) Insoluble Soluble Hydrolysis protection in polyethylene terephthalate (PET)

[0061] To evaluate the hydrolysis protection effect in PET, 1.5 wt.% of each of the carbodiimides tested was dispersed into PET using a Werner & Pfleiderer ZSK 25 laboratory twin-screw extruder prior to the measurement described below. The resulting granules were then used to produce the F3 standard test specimens used to measure tear strength on an Arburg Allrounder 320 S 150-500 injection molding machine.

[0062] For the hydrolysis test, these F3 standard test specimens were stored in water at a temperature of 90°C, and their tensile strength was measured in MPa. Table 2 shows the relative tensile strengths = (tensile strength after x days of storage / tensile strength after 0 days) x 100. A value of 70-75% is usually considered the lower limit for relative tensile strength.

[0063] The results are listed in Table 3: Table 3 Relative tear strength (%) Example 7 (cf.) (PET) Example 8 (cf.) (PET / CDI A) Example 9 (req.) (PET / CDI C) 0 days 100 100 100 5 days 100 100 100 10 days 51 100 100 15 days - 100 100 20 days - 100 100 25 days - 52 81 28 days - - 41 cf. = comparative example, req. = according to the invention Tests on the pastillability and dosability of solid carbodiimides

[0064] To clarify the processability, handling, and dosing properties of the various solid carbodiimides, they were compared with regard to appearance, pastillability, and softening point. The softening points were determined using a Koffler bench.

[0065] The results are listed in Table 4: Carbodiimid Appearance (at RT) Pastillability Dosability (T up to 40 °C) Softening point (°C) CDI (B), cf. soft, sticky mass not possible - < 20 CDI (D), cf. hard, sticky mass not possible - > 120 CDI (C), required firm, brittle very good very good approx. 80 cf. = comparative example, req. = according to the invention

[0066] The results in Table 4 show that the inventive carbodiimides based on diisopropyltoluoyl diisocyanate end-capped with a monoisocyanate exhibit excellent pastillability and a high softening point compared to the polymeric carbodiimide based on diethyltoluoyl diisocyanate, also end-capped with a monoisocyanate, and compared to Carbodiimide D. They thus offer advantages in the formulation and metering of the solid for stabilizing ester-based polymers. The inventive Carbodiimide E is liquid and can be metered as such.

Claims

1. Carbodiimides of formula (I) in which R may be identical or different and is selected from -NCN-RI and -NHCOORIII, wherein RI represents C1-C22-alkyl, C6-C12-cycloalkyl, C6-C18-aryl or C6-C18-aralkyl, preferably triisopropylphenyl, and RIII represents an alkylated polyoxyalkylene radical, R1, R2 and R3 each independently of one another represent methyl, i-propyl or n-propyl, wherein on each benzene ring one of the radicals R1, R2 and R3 is methyl and n is from 0 to 500, preferably from 1 to 50.

2. Carbodiimides according to Claim 1, wherein R1, R2 and R3 each independently of one another represent methyl- or i-propyl-.

3. Carbodiimides according to Claim 1 or 2, wherein the carbodiimide content is 2-17% by weight.

4. Carbodiimides according to one or more of Claims 1 to 3, wherein in formula (I) R represents NCN-RI, n is from 0 to 500, preferably from 1 to 100, particularly preferably from 1 to 50 and the carbodiimide content is preferably 10-17% by weight, particularly preferably 11-15% by weight and most preferably 13-14% by weight.

5. Carbodiimides according to one or more of Claims 1 to 3, wherein in formula (I) R represents -NHCOORIII, n is from 0 to 20, preferably from 1 to 10, particularly preferably from 3 to 8, and the carbodiimide content is preferably from 4% to 13% by weight, particularly preferably from 10% to 13% by weight.

6. Carbodiimides according to one or more of Claims 1 to 3, wherein in formula (I) R represents -NHCOORIII and RIII represents an alkylated polyoxyalkylene radical, n is from 0 to 20, preferably n is from 1 to 10, particularly preferably from 1 to 4 and most preferably from 2 to 3 and the carbodiimide content is preferably 2-10% by weight, particularly preferably 4-8% by weight and most preferably 5-7% by weight.

7. Carbodiimides according to Claim 6, wherein RIII represents monoalkylated polyethylene glycol ethers, preferably polyethylene glycol monomethyl ethers, preferably having molar masses of 200-600 g / mol, particularly preferably having molar masses of 350-550 g / mol.

8. Process for producing carbodiimides according to one or more of Claims 1 to 7 comprising the steps of: a) carbodiimidization of aromatic diisocyanates of formula (II) to eliminate carbon dioxide at temperatures of 80°C to 200°C in the presence of catalysts and optionally solvent and b) functionalization of the free NCO groups of the carbodiimides obtained in step (a) with alcohols of formula NORIII, wherein R1 to R3 and RIII are as defined above for the compounds of formula (I).

9. Process for producing carbodiimides according to one or more of Claims 1 to 7 comprising the steps of: a) partial, preferably < 50%, functionalization of the free NCO groups of aromatic diisocyanates of formula (II) with alcohols of formula NORIII and b) subsequent carbodiimimidization of the partially functionalized aromatic diisocyanates of formula (II) obtained in step a) to eliminate carbon dioxide at temperatures of 80°C to 200°C in the presence of catalysts and optionally solvent, wherein R1 to R3 and RIII are as defined above for the compounds of formula (I)10. Process for producing carbodiimides according to one or more of Claims 1 to 7 comprising carbodiimidization of aromatic diisocyanates of formula (II) to eliminate carbon dioxide at temperatures of 80°C to 200°C in the presence of catalysts and optionally solvent, wherein before, during or after the carbodiimidization of the diisocyanates monoisocyanates of formula OCN-RI are added and wherein R1 to R3 and RI are as defined above for the compounds of formula (I).

11. Process according to any of Claims 8 to 10, wherein the aromatic diisocyanates of formula (II) employed are compounds of formulae (III) and / or (IV).

12. Process according to one or more of Claims 8 to 11, wherein R = -NCN-RI, wherein RI is as defined above for the compounds of formula (I) and the melt of the carbodiimide obtained in the carbodiimization is pelletized in unpurified form or after purification.

13. Use of the carbodiimides according to any of Claims 1 to 7 as an inhibitor against hydrolytic decomposition in ester-based polymers, preferably polymers selected from polyester polyols, polyethylene terephthalate (PET), polybutylene terephthalate (PBT), polytrimethylene terephthalate (PTT), copolyesters such as modified polyesters of cyclohexanediol and terephthalic acid (PCTA), thermoplastic polyester elastomers (TPE E), ethylene vinyl acetate (EVA), polylactic acid (PLA) and / or PLA derivatives, polybutylene adipate-terephthalates (PBAT), polybutylene succinates (PBS), polyhydroxyalkanoates (PHA), polyurethane elastomers, preferably thermoplastic polyurethanes (TPU), and blends, preferably PA / PET or PHA / PLA blends.

14. Use of the carbodiimides according to any of Claims 1 to 8 as protection against hydrolytic degradation in thermoplastic polyurethane (TPU).

15. Composition containing at least one inventive carbodiimide according to any of Claims 1 to 7 and at least one ester-based polymer, preferably an ester-based polymer selected from polyester polyols, polyethylene terephthalate (PET), polybutylene terephthalate (PET), polytrimethylene terephthalate (PTT), copolyesters such as modified polyesters of cyclohexanediol and terephthalic acid (PCTA), thermoplastic polyester elastomers (TPE E), ethylene vinyl acetate (EVA), polylactic acid (PLA) and / or PLA derivatives, polybutylene adipate-terephthalates (PBAT), polybutylene succinates (PBS), polyhydroxyalkanoates (PHA), polyurethane elastomers, in particular thermoplastic polyurethanes (TPU), and blends, such as in particular PA / PET or PHA / PLA blends.